I finally discovered a way to get the power off.
Press in a paperclip into the small reset port along the left edge. As long as you hold it in there the screen will be blank and when you release it the prime will once again begin booting. I held down the power button and both the up and down volume buttons all at the same time and then released the paper clip. The screen is back and it did not reset/reboot.
I am going to leave it like this for 2 hours, while connected to a wall outlet and then try one last time to boot it.
I really don't want to lose everything.